Steambox 2021: even faster

After Saturday’s work I got my steambox starting even faster.

I am excited to have my steambox start so quickly, but waiting for a mostly useless desktop manager annoys me. I fixed that today! Here is what I did in short:

1. Use xsession style desktop management
2. Use the steamos window manager by default
3. If a touchfile exists, use a traditional desktop
4. Add a tool to steam as a game that creates the touchfile

🔗 XSession

This setup lets the user run a script that will initialize their window manager etc. I use this on my laptop and generally enjoy the flexibility.

First, I create a file called /usr/share/xsessions/xsession.desktop and put the following in the file:

[Desktop Entry]
Name=Xsession
Comment=This runs ~/.xsession
Exec=/etc/X11/Xsession

Now, display managers (like lightdm, in my case) will offer this as one of the window managers to select when you log in. We’ll write the actual ~/.xsession later.

🔗 steampcompmgr

My friend Wes pointed out this repository as possibly the window manager that SteamOS uses. Because the steambox and my laptop are both running Ubuntu 20.04 I decided to just build it on my laptop and scp it to the steambox. Here’s how I built it:

sudo apt install libsdl-image1.2-dev libxcomposite-dev libxdamage-dev
./configure
make

The produced binary (steamcompmgr) worked on my laptop by hiding all of my windows, to which I shrugged, killed it, and assumed all was well. I placed that binary in /usr/local/bin/steamcmpmgr on the steambox, ran ldd on it to make sure no libraries were missing, and moved on.

🔗 ~/.xsession

Here’s the contents of the .xsession file I created:

#!/bin/sh

echo "Starting xsession: $(date)"

steam -bigpicture &

if [ -e "$HOME/.de" ]; then
  rm "$HOME/.de"
  exec startxfce4
fi

exec steamcompmgr

It should be pretty self explanatory. The main thing I’d point out is that you really want your .xsession to end by exec‘ing your window manager, otherwise weird things can happen with the shell running the window manager.

At this point I put ensured that xsession was enabled by default to test my progress. I did that by making /etc/lightdm/lightdm.conf look like this:

[Seat:*]
autologin-session=xsession
autologin-user=frew
autologin-user-timeout=0

It works!

🔗 Desktop Environment

The original SteamOS had two users, steam and desktop. While I appreciate the simplicity of that solution, it means you can never run steam outside of big picture mode, which ends up being limiting in some cases. To allow dropping into the desktop (in part aided because rebooting is so fast that it’s the easiest option) I just touch ~/.de. In /usr/local/bin/enable-desktop-environment I created the following script:

#!/bin/sh

# works with /home/frew/.xsession to create a touchfile to enable xfce

touch "$HOME/.de"

Rob pointed out that I should be able to use .dmrc to select which window manager I start with to avoid the touch file, which is true, but my instinct is that the path I’ve selected is closer to how I run my laptop and thus more likely to keep working as the ecosystem evolves. (I’ll notice if it breaks.)

Next, I created a .desktop entry at /usr/share/applications/enable-desktop-environment.desktop so that I’d be able to add a custom game for it:

[Desktop Entry]
Encoding=UTF-8
Version=1.0
Type=Application
Terminal=false
Exec=/usr/local/bin/enable-desktop-environment
Name=Enable Desktop Environment

Finally, I created a custom game entry for this. Now, when I Steam Library, one of the entries is Enable Desktop Environment. If I run this “game” and then reboot I still end up in steam, but can exit Big Picture Mode and interact with the normal Steam UI.

(Affiliate links below.)

Recently Brendan Gregg’s Systems Performance got its second edition released. He wrote about it here. I am hoping to get a copy myself soon. I loved the first edition and think the second will be even more useful.

At the end of 2019 I read BPF Performance Tools. It was one of my favorite tech books I read in the past five years. Not only did I learn how to (almost) trivially see deeply inside of how my computer is working, but I learned how that works via the excellent detail Gregg added in each chapter. Amazing stuff.

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